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mm/hmm: remove hmm_range_dma_map and hmm_range_dma_unmap
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These two functions have never been used since they were added.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: John Hubbard <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
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Christoph Hellwig authored and jgunthorpe committed Nov 23, 2019
1 parent d28c2c9 commit 93f4e73
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Showing 2 changed files with 0 additions and 170 deletions.
23 changes: 0 additions & 23 deletions include/linux/hmm.h
Original file line number Diff line number Diff line change
Expand Up @@ -230,34 +230,11 @@ static inline uint64_t hmm_device_entry_from_pfn(const struct hmm_range *range,
* Please see Documentation/vm/hmm.rst for how to use the range API.
*/
long hmm_range_fault(struct hmm_range *range, unsigned int flags);

long hmm_range_dma_map(struct hmm_range *range,
struct device *device,
dma_addr_t *daddrs,
unsigned int flags);
long hmm_range_dma_unmap(struct hmm_range *range,
struct device *device,
dma_addr_t *daddrs,
bool dirty);
#else
static inline long hmm_range_fault(struct hmm_range *range, unsigned int flags)
{
return -EOPNOTSUPP;
}

static inline long hmm_range_dma_map(struct hmm_range *range,
struct device *device, dma_addr_t *daddrs,
unsigned int flags)
{
return -EOPNOTSUPP;
}

static inline long hmm_range_dma_unmap(struct hmm_range *range,
struct device *device,
dma_addr_t *daddrs, bool dirty)
{
return -EOPNOTSUPP;
}
#endif

/*
Expand Down
147 changes: 0 additions & 147 deletions mm/hmm.c
Original file line number Diff line number Diff line change
Expand Up @@ -691,150 +691,3 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags)
return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT;
}
EXPORT_SYMBOL(hmm_range_fault);

/**
* hmm_range_dma_map - hmm_range_fault() and dma map page all in one.
* @range: range being faulted
* @device: device to map page to
* @daddrs: array of dma addresses for the mapped pages
* @flags: HMM_FAULT_*
*
* Return: the number of pages mapped on success (including zero), or any
* status return from hmm_range_fault() otherwise.
*/
long hmm_range_dma_map(struct hmm_range *range, struct device *device,
dma_addr_t *daddrs, unsigned int flags)
{
unsigned long i, npages, mapped;
long ret;

ret = hmm_range_fault(range, flags);
if (ret <= 0)
return ret ? ret : -EBUSY;

npages = (range->end - range->start) >> PAGE_SHIFT;
for (i = 0, mapped = 0; i < npages; ++i) {
enum dma_data_direction dir = DMA_TO_DEVICE;
struct page *page;

/*
* FIXME need to update DMA API to provide invalid DMA address
* value instead of a function to test dma address value. This
* would remove lot of dumb code duplicated accross many arch.
*
* For now setting it to 0 here is good enough as the pfns[]
* value is what is use to check what is valid and what isn't.
*/
daddrs[i] = 0;

page = hmm_device_entry_to_page(range, range->pfns[i]);
if (page == NULL)
continue;

/* Check if range is being invalidated */
if (mmu_interval_check_retry(range->notifier,
range->notifier_seq)) {
ret = -EBUSY;
goto unmap;
}

/* If it is read and write than map bi-directional. */
if (range->pfns[i] & range->flags[HMM_PFN_WRITE])
dir = DMA_BIDIRECTIONAL;

daddrs[i] = dma_map_page(device, page, 0, PAGE_SIZE, dir);
if (dma_mapping_error(device, daddrs[i])) {
ret = -EFAULT;
goto unmap;
}

mapped++;
}

return mapped;

unmap:
for (npages = i, i = 0; (i < npages) && mapped; ++i) {
enum dma_data_direction dir = DMA_TO_DEVICE;
struct page *page;

page = hmm_device_entry_to_page(range, range->pfns[i]);
if (page == NULL)
continue;

if (dma_mapping_error(device, daddrs[i]))
continue;

/* If it is read and write than map bi-directional. */
if (range->pfns[i] & range->flags[HMM_PFN_WRITE])
dir = DMA_BIDIRECTIONAL;

dma_unmap_page(device, daddrs[i], PAGE_SIZE, dir);
mapped--;
}

return ret;
}
EXPORT_SYMBOL(hmm_range_dma_map);

/**
* hmm_range_dma_unmap() - unmap range of that was map with hmm_range_dma_map()
* @range: range being unmapped
* @device: device against which dma map was done
* @daddrs: dma address of mapped pages
* @dirty: dirty page if it had the write flag set
* Return: number of page unmapped on success, -EINVAL otherwise
*
* Note that caller MUST abide by mmu notifier or use HMM mirror and abide
* to the sync_cpu_device_pagetables() callback so that it is safe here to
* call set_page_dirty(). Caller must also take appropriate locks to avoid
* concurrent mmu notifier or sync_cpu_device_pagetables() to make progress.
*/
long hmm_range_dma_unmap(struct hmm_range *range,
struct device *device,
dma_addr_t *daddrs,
bool dirty)
{
unsigned long i, npages;
long cpages = 0;

/* Sanity check. */
if (range->end <= range->start)
return -EINVAL;
if (!daddrs)
return -EINVAL;
if (!range->pfns)
return -EINVAL;

npages = (range->end - range->start) >> PAGE_SHIFT;
for (i = 0; i < npages; ++i) {
enum dma_data_direction dir = DMA_TO_DEVICE;
struct page *page;

page = hmm_device_entry_to_page(range, range->pfns[i]);
if (page == NULL)
continue;

/* If it is read and write than map bi-directional. */
if (range->pfns[i] & range->flags[HMM_PFN_WRITE]) {
dir = DMA_BIDIRECTIONAL;

/*
* See comments in function description on why it is
* safe here to call set_page_dirty()
*/
if (dirty)
set_page_dirty(page);
}

/* Unmap and clear pfns/dma address */
dma_unmap_page(device, daddrs[i], PAGE_SIZE, dir);
range->pfns[i] = range->values[HMM_PFN_NONE];
/* FIXME see comments in hmm_vma_dma_map() */
daddrs[i] = 0;
cpages++;
}

return cpages;
}
EXPORT_SYMBOL(hmm_range_dma_unmap);

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